IPC 2024: In-Situ Determination of Pipe Body Fracture Toughness Using Planing-Induced Microfracture Method

Fracture toughness is a critical factor in assessing pipeline integrity, particularly for vintage pipelines where material toughness data may be unavailable. Conventional methods for determining fracture toughness often require destructive testing, which can be costly and impractical. This paper introduces a novel, minimally invasive approach for in-situ toughness assessment using the Planing-Induced Microfracture (PIM) method. This technique utilizes a specialized blade with a central opening that induces tensile stress in the material as it moves across the pipe surface, generating microfractures. The characteristics of residual ligaments on the fractured surfaces correlate with the material’s fracture toughness, providing valuable data for integrity assessments.

Initial proof-of-concept testing on 30 pipeline samples demonstrated that the method could predict KIc values within ±20% accuracy compared to destructive lab testing. Further advancements have led to the development of a portable prototype instrument, allowing field application without requiring cutouts. This paper presents the methodology, prototype field instrument, and recent test results, highlighting its potential as a practical nondestructive evaluation (NDE) tool to support pipeline integrity management.